1. Field of the Invention
The present invention relates to a vehicle air conditioning system for controlling air conditioning state of a vehicle based on a temperature measurement of a non-contacting temperature sensor.
2. Description of Related Art
One type of previously proposed vehicle air conditioning system uses a non-contacting temperature sensor (e.g., infrared sensor) to measure a surface temperature of an occupant seated in a vehicle seat and controls air conditioning state of the passenger compartment (e.g., the temperature and the flow rate of air discharged from a discharge opening of the air conditioning system) based on the measured surface temperature of the occupant. One such an air conditioning system is disclosed in Japanese Unexamined Patent publication No. 2002-172926. This air conditioning system will be referred to as a first type air conditioning system.
Another type of previously proposed air conditioning system controls air conditioning state around a driver seat and air conditioning state around a front-passenger seat independently of each other. One such an air conditioning system is disclosed in Japanese Unexamined Patent publication No. 2002-144839. This air conditioning system will be referred to as a second type air conditioning system.
It is conceivable to combine the first type air conditioning system and the second type air conditioning system in such a manner that the surface temperature of the driver seated in the driver seat and the surface temperature of the occupant seated in the front-passenger seat are measured with non-contacting temperature sensors, and the air conditioning state around the driver seat and the air conditioning state around the front-passenger seat are controlled independently of each other based on the measured surface temperature of the driver in the driver seat and the measured surface temperature of the occupant in the front-passenger seat.
However, in such an air conditioning system, when the occupant is absent in the front-passenger seat, the surface temperature of the front-passenger seat is measured instead of the surface temperature of the occupant in the front-passenger seat. Thus, when the air conditioning state around the front-passenger seat is controlled based on the surface temperature of the front-passenger seat, the air conditioning state around the driver seat and the air conditioning state around the front-passenger seat substantially differ from one another. In such a case, an air flow will be supplied from the front-passenger seat air conditioning zone to the driver seat air conditioning zone, resulting in uncomfortable feeling of the driver. Furthermore, in the case where the air conditioning control operation is performed without considering presence or absence of the occupant in the seat, when the occupant returns the seat after a predetermined period of absence, the occupant may feel uncomfortableness.